Three-year outcomes of preoperative chemoradiotherapy plus nivolumab in microsatellite stable and microsatellite instability-high locally advanced rectal cancer.

BACKGROUND: Preoperative chemoradiotherapy (CRT) followed by surgery is the standard treatment for locally advanced rectal cancer (LARC). We reported the short-term outcomes of the VOLTAGE trial that investigated the safety and efficacy of preoperative CRT followed by nivolumab and surgery. Here, we present the 3-year outcomes of this trial. METHODS: Thirty-nine patients with microsatellite stable (MSS) LARC and five patients with microsatellite instability-high (MSI-H) LARC underwent CRT (50.4 Gy) followed by five doses of nivolumab (240 mg) and surgery. The 3-year relapse-free survival (RFS), overall survival (OS), and associations with biomarkers were evaluated. RESULTS: The 3-year RFS rates in patients with MSS and MSI-H were 79.5% and 100%, respectively, and the 3-year OS rates were 97.4% and 100%, respectively. Of the MSS patients, those with pre-CRT PD-L1 positivity, pre-CRT high CD8 + T cell/effector regulatory T cell (eTreg) ratio, pre-CRT high expression of Ki-67, CTLA-4, and PD-1 had a trend toward better 3-year RFS than those without. CONCLUSIONS: Three-year outcomes of patients with MSI-H were better than those of patients with MSS. PD-L1 positivity, elevated CD8/eTreg ratio, and high expression of Ki-67, CTLA-4, and PD-1 could be positive predictors of prognosis in patients with MSS. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02948348.

Development of a laparoscopic sigmoidectomy simulator: Sigmaster.

The sigmoid colon simulator was designed to accurately reproduce the anatomical layer structure and the arrangement of characteristic organs in each layer, and to have conductivity so that energy devices can be used. Dry polyester fibers were used to reproduce the layered structures, which included characteristic blood vessels, nerve sheaths, and intestinal tracts. The adhesive strength of the layers was controlled to allow realistic peeling techniques. The features of the Sigmaster are illustrated through a comparison of simulated sigmoidectomy using Sigmaster and actual surgery. We developed a laparoscopic sigmoidectomy simulator called Sigmaster. Sigmaster is a training device that closely reproduces the membrane structures of the human body and allows surgeons to experience the entire laparoscopic sigmoidectomy process.

Long-term survival and functional outcomes of laparoscopic surgery for clinical stage I ultra-low rectal cancers located within 5 cm of the anal verge: A prospective phase II trial (Ultimate trial).

OBJECTIVE: To clarify the long-term oncological outcomes and postoperative anal, urinary, and sexual functions after laparoscopic surgery for clinical stage I very low rectal carcinoma located near the anal canal. SUMMARY BACKGROUND DATA: Laparoscopic surgery is widely applied for rectal cancer; however, concerns remain, with some studies showing poorer outcomes compared to open surgery. METHODS: This single-arm, phase II trial included patients registered preoperatively from 47 institutions in Japan. The planned sample size was 300. The primary endpoint was the 3-year local recurrence rate. Anal, urinary, and sexual functions were evaluated using a prospective questionnaire. RESULTS: Three-hundred patients were registered between January 2014 and March 2017. Anus-preserving surgery was performed in 278 (93%), including 172 who underwent intersphincteric resection (58%) and 106 (36%) who underwent low anterior resection. The 3-year cumulative local recurrence rate was 6.3%. At 3 years postoperatively, 87% of patients used their own anus, and the median incontinence score improved from 12 at 3 months to 8 at 3 years. Only 5% of patients had severe incontinence (incontinence score of 16 points). Postoperative urinary function evaluation showed that International Prostate Symptom Score and Overactive Bladder Symptom Score decreased 1 week after surgery, but recovered to preoperative level 1 month after surgery. International Consultation on Incontinence Questionnaire-Sort Form remained almost stable after surgery. Sexual function evaluation using the International Index of Erectile Function-5 and International Index of Erectile Function-15 revealed that the patients had deteriorated 3 months after surgery but had recovered only slightly by 6 months. CONCLUSIONS: Laparoscopic surgery achieves feasible long-term oncological outcomes and a high rate of anus preservation with moderate anal function, and an acceptable incontinence score. While urinary function recovered rapidly, sexual function showed poor recovery.

Cytological Analysis of the Surgical Field During Transanal Total Mesorectal Excision for Rectal Cancer: A Prospective Study.

BACKGROUND: An unexpectedly large number of patients experienced local recurrence with transanal total mesorectal excision in Norway. This appears to be associated with cancer cell spillage during surgery. OBJECTIVE: To investigate the surgical field cytology during transanal total mesorectal excision. DESIGN: This was a prospective cohort study. SETTINGS: This study was conducted at a single center between June and December 2020. PATIENTS: Forty patients with rectal cancer underwent transanal total mesorectal excision. Following the irrigation of the surgical field, the water specimens were cytologically evaluated at six representative steps. The first sample was used as an initial control. The second, third, fourth, fifth, and sixth samples were collected after the 1st purse-string suture, rectotomy, the 2nd purse-string suture, specimen resection, and anastomosis, respectively. The clinicopathological features and intraoperative complications of the patients were reviewed. MAIN OUTCOME MEASURES: The primary outcome was to evaluate the presence of cancer cells in washing cytological samples. RESULTS: Of the 40 consecutive patients enrolled in this study, 18 patients underwent neoadjuvant chemoradiotherapy. Incomplete first pursestring suture and rectal perforation were observed in 4 (10.0%) and 3 (7.5%) cases, respectively. In the first sample, 31 (77.5%) patients had malignant cells. Malignant findings were detected in two patients (5.0%) from the second to fifth samples. None of the sixth sample exhibited any malignant findings. LIMITATIONS: This single center study had a small sample size. CONCLUSIONS: Cancer cells were initially detected by cytology, but only a few were observed throughout the procedure; however, cancer cells were not detected in the final surgical field. Further follow-up and novel studies are required to obtain clinically significant findings using cytology during transanal total mesorectal excision. See Video Abstract.

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy versus R0 resection for resectable colorectal cancer with peritoneal metastases and low peritoneal cancer index scores: a collaborative observational study from Korea and Japan.

BACKGROUND: The benefits of hyperthermic intraperitoneal chemotherapy (HIPEC) after cytoreductive surgery (CRS) for colorectal cancer with peritoneal metastasis (CPM) remain controversial. R0 resection without peritoneal stripping might be as effective as CRS plus HIPEC. The authors aimed to compare the long-term oncological outcomes of patients with CPM and peritoneal cancer index (PCI) scores less than or equal to 6 who underwent R0 resection in Japan with those who underwent CRS plus HIPEC in Korea. MATERIALS AND METHODS: This international, retrospective cohort study was conducted in Korea and Japan using a prospectively collected clinical database. Patients who underwent surgery from July 2014 to December 2021 for CPM with a PCI score of less than or equal to 6 and completeness of the cytoreduction score-0 were included. The primary outcome was relapse-free survival (RFS), and the secondary outcomes were overall survival, peritoneal RFS (PRFS), and postoperative outcomes. RESULTS: The 3-year RFS was significantly longer in the CRS+HIPEC group than in the R0 resection group: 35.9% versus 6.9% ( P <0.001); 31.0% versus 6.7% ( P =0.040) after propensity score matching. The median PRFS was significantly longer in the CRS+HIPEC group than in the R0 resection group: 24.5 months versus 17.2 months ( P =0.017). The 3-year overall survival and postoperative complications did not significantly differ between the two groups. CONCLUSIONS: RFS and PRFS rates were significantly prolonged after CRS plus HIPEC, whereas postoperative complications and length of hospital stay were not increased. Therefore, curative CRS plus HIPEC may be considered a treatment strategy for selected patients with resectable CPM and low PCI scores.

Total neoadjuvant therapy followed by a watch-and-wait strategy for patients with rectal cancer (TOWARd): protocol for single-arm phase II/III confirmatory trial (JCOG2010).

BACKGROUND: Radical surgery is the standard treatment for rectal cancer, but can impact quality of life. Recently, the concept of total neoadjuvant therapy with a watch-and-wait strategy has been proposed in which patients with a cCR after total neoadjuvant therapy do not proceed to surgery. However, most investigations of a watch-and-wait strategy have reported cases where cCR was achieved coincidentally via total neoadjuvant therapy. The aim is to assess whether total neoadjuvant therapy is effective in early-stage rectal cancer in patients that achieve cCR and are offered a watch-and-wait strategy. METHODS: JCOG2010 (TOWARd) is a multi-institutional, single-arm phase II/III confirmatory investigation of the safety and efficacy of total neoadjuvant therapy followed by a watch-and-wait strategy for rectal cancer. Key eligibility criteria include cT2-3 N0 M0 rectal adenocarcinoma, tumour diameter less than or equal to 5 cm, age 18-75 years, performance status 0-1, and no history of pelvic irradiation or rectal surgery. Total neoadjuvant therapy involves neoadjuvant chemoradiotherapy (capecitabine and radiotherapy: 45 Gy/25 fractions to the whole pelvis plus boost of 5.4 Gy/3 fractions to the primary tumour) followed by consolidation chemotherapy (four cycles of capecitabine/oxaliplatin). Patients will be re-staged every 8 weeks after total neoadjuvant therapy, and those who achieve cCR will undergo a watch-and-wait strategy, those with near complete response will undergo a watch-and-wait strategy or local resection, and those with an incomplete response will undergo radical surgery. The primary endpoint is the cCR rate in phase II and 5-year overall survival in phase III. Secondary endpoints include postoperative anal, urinary, and sexual function. A total of 105 patients (phase II, 40 patients; phase III, 65 patients) will be enrolled over 3.5 years. CONCLUSION: This trial will determine whether total neoadjuvant therapy and a watch-and-wait strategy is an effective alternative to radical surgery for early-stage rectal cancer in patients with cT2-3 N0 M0 and tumour size less than or equal to 5 cm. REGISTRATION NUMBER: jRCTs031220288 (https://jrct.niph.go.jp/en-latest-detail/jRCTs031220288).

Can the Single-stapling Technique Following Intersphincteric Resection with Transanal Total Mesorectal Excision Become the New Standard Anastomosis?

For transanal total mesorectal excision (TaTME), the indication for single-stapling technique (SST) has been expanded to include lower anastomosis, even in intersphincteric resection (ISR). We focused on the anastomotic techniques following ISR with TaTME and examined the feasibility and safety of the SST below the anorectal junction (ARJ). Data on postoperative anastomosis-related complications and anorectal function was evaluated in comparison to conventional manual hand-sewn coloanal anastomosis in ISR with TaTME. We examined patients with 3-6 cm tumors from the anal verge who underwent ISR with TaTME between January 2018 and March 2020, and whose anastomotic line was located below the ARJ. Postoperative short-term outcomes and anorectal functions were compared. We also analyzed the effects of various factors on major low anterior resection syndrome (LARS) using multivariate logistic regression analysis. In total, 87 patients-48 in the hand-sewn anastomosis group and 39 in the SST group-were included in this study. SST below the ARJ in ISR with TaTME did not exacerbate surgical outcomes, including anastomosis-related complications. The SST group had a significantly lower LARS score as compared to the hand-sewn anastomosis group, and the proportion of major LARS was significantly lower. Only hand-sewn anastomosis was identified as a statistically significant independent risk factor for major LARS. In TaTME, SST below the ARJ was safe and feasible and had a lower negative impact on postoperative anastomosis-related complications and anorectal function as compared to hand-sewn anastomosis. Thus, SST is a promising anastomotic option for patients with low-lying rectal tumors.

Transanal Total Mesorectal Excision for Rectal Cancer: Toward Standardization of the Surgical Technique.

Laparoscopic surgery is widely used for rectal cancer; however, this technique is challenging due to tapering of the mesorectum in the pelvis, and the forward angle of the distal rectum, which renders this part of the rectum less accessible from the abdominal cavity. Hence, concerns regarding its safety and curability have been raised, particularly for inadequate distal and circumferential resection margins. Recently, transanal total mesorectal excision (TaTME), which involves endoscopic total mesorectal excision (TME) retrogradely from the anal side, has attracted attention worldwide as a solution to these problems. TaTME is superior to the conventional laparoscopic approach for rectal cancer in terms of both oncological and functional preservations. However, a shallow learning curve caused by the unfamiliar anatomical view from the anal side can pose challenges. Therefore, an efficient educational system needs to be established. Randomized controlled trials comparing conventional laparoscopic TME with TaTME are ongoing to demonstrate the usefulness of TaTME. This article reviews changes in the surgical treatment of rectal cancer, with a focus on TaTME, and describes the indications, surgical techniques, and training curricula for TaTME.

Utility of circulating tumour DNA for prognosis and prediction of therapeutic effect in locally recurrent rectal cancer: study protocol for a multi-institutional, prospective observational study (JCOG1801A1, CAP-LR study).

INTRODUCTION: In locally recurrent rectal cancer (LRRC), surgery is a standard treatment for resectable disease. However, short-term and long-term outcomes are unsatisfactory due to the invasive nature of surgical procedures and the high proportion of local recurrence. Consequently, the identification of reliable prognostic and predictive biomarkers to guide treatment decisions may improve outcomes. The presence of circulating tumour DNA (ctDNA) in plasma after surgery may signify the presence of minimal residual disease (MRD) in various cancers. Therefore, we have launched a multi-institutional prospective observational study of ctDNA for MRD detection in conjunction with JCOG1801, a randomised, controlled phase III trial evaluating the efficacy of preoperative chemoradiotherapy (pre-CRT) compared with up-front surgery for LRRC (jRCTs031190076, NCT04288999). METHODS AND ANALYSIS: JCOG1801A1 is the first correlative study that assesses ctDNA in LRRC patients enrolled in JCOG1801. Patients randomised to up-front surgery will provide whole blood samples at three time points (prior to surgery, after surgery and after postoperative chemotherapy); those to pre-CRT will provide at five time points (prior to pre-CRT, after pre-CRT, prior to surgery, after surgery and after postoperative chemotherapy). Cell-free DNA will be extracted from plasma and analysed by Guardant Reveal, a tumour tissue-agnostic assay that assesses both genomic alterations and methylation patterns to determine the presence or absence of ctDNA. We will compare the prognosis and treatment response of patients according to their ctDNA status after surgery and at other time points. ETHICS AND DISSEMINATION: The study protocol received approval from the Institutional Review Board of National Cancer Center Hospital East on behalf of the participating institutions in February 2023. The study is conducted in accordance with the precepts established in the Declaration of Helsinki and Ethical Guidelines for Medical and Biological Research Involving Human Subjects. Written informed consent will be obtained from all eligible patients prior to registration.

Assessment of Elastic Laminal Invasion Contributes to an Objective pT3 Subclassification in Colon Cancer.

The extent of tumor spread influences on the clinical outcome, and which determine T stage of colorectal cancer. However, pathologic discrimination between pT3 and pT4a in the eighth edition of the American Joint Committee on Cancer (AJCC)-TNM stage is subjective, and more objective discrimination method for deeply invasive advanced colon cancer is mandatory for standardized patient management. Peritoneal elastic laminal invasion (ELI) detected using elastic staining may increase the objective discrimination of deeply invasive advanced colon cancer. In this study, we constructed ELI study group to investigate feasibility, objectivity, and prognostic utility of ELI. Furthermore, pT classification using ELI was investigated based on these data. At first, concordance study investigated objectivity using 60 pT3 and pT4a colon cancers. Simultaneously, a multi-institutional retrospective study was performed to assess ELI's prognostic utility in 1202 colon cancer cases from 6 institutions. In the concordance study, objectivity, represented by κ, was higher in the ELI assessment than in pT classification. In the multi-institutional retrospective study, elastic staining revealed that ELI was a strong prognostic factor. The clinical outcome of pT3 cases with ELI was significantly and consistently worse than that of those without ELI. pT classification into pT3 without ELI, pT3 with ELI, and pT4a was an independent prognostic factor. In this study, we revealed that ELI is an objective method for discriminating deeply invasive advanced colon cancer. Based on its feasibility, objectivity, and prognostic utility, ELI can subdivide pT3 lesions into pT3a (without ELI) and pT3b (with ELI).

Short-term outcomes following intracorporeal vs. extracorporeal anastomosis after laparoscopic right and left-sided colectomy: a propensity score-matched study.

BACKGROUND: To compare the short-term outcomes of patients undergoing intracorporeal anastomosis (IA) during laparoscopic colectomy to those undergoing extracorporeal anastomosis (EA). METHODS AND MATERIALS: The study was a single-centre retrospective propensity score-matched analysis conducted. Consecutive patients who underwent elective laparoscopic colectomy without the double stapling technique between January 2018 and June 2021 were investigated. The main outcome was overall postoperative complications within 30 days after the procedure. The authors also performed a sub-analysis of the postoperative results of ileocolic anastomosis and colocolic anastomosis, respectively. RESULTS: A total of 283 patients were initially extracted; after propensity score matching, there were 113 patients in each of the IA and EA groups. There were no differences in patient characteristics between the two groups. The IA group had a significantly longer operative time than the EA group (208 vs. 183 min, P =0.001). The rate of overall postoperative complications was significantly lower in the IA group ( n =18, 15.9%) than in the EA group ( n =34, 30.1%; P =0.02), especially in colocolic anastomosis after left-sided colectomy (IA: 23.8% vs. EA: 59.1%; P =0.03). Postoperative inflammatory marker levels were significantly higher in the IA group on postoperative day 1 but not on postoperative day 7. There was no difference in the postoperative lengths of hospital stay between the two groups, and no deaths occurred. CONCLUSION: The data suggest that performing IA during laparoscopic colectomy can potentially reduce the risk of postoperative complications, especially in colocolic anastomosis after left-sided colectomy.

Survival outcomes following salvage abdominoperineal resection for recurrent and persistent anal squamous cell carcinoma.

INTRODUCTION: The primary treatment for locoregional failure following chemoradiotherapy for squamous cell carcinoma of the anus (SCCA) is salvage abdominoperineal resection (APR). However, it is necessary to distinguish between recurrent and persistent diseases because of their varied pathologies. We aimed to clarify the survival outcomes following salvage APR for recurrent and persistent diseases and investigate the significance of salvage APR. MATERIALS AND METHODS: This multicentre retrospective cohort study used clinical data from 47 hospitals. All patients were diagnosed with SCCA and underwent definitive radiotherapy as the primary treatment between 1991 and 2015. Overall survival (OS) was compared between the following cohorts: salvage APR for recurrence, salvage APR for persistence, non-salvage APR for recurrence, and non-salvage APR for persistence. RESULTS: Five-year OS of salvage APR for recurrence, salvage APR for persistence, non-salvage APR for recurrence, and non-salvage APR for persistence were 75% (46%-90%), 36% (21%-51%), 42% (21%-61%), and 47% (33%-60%), respectively. OS of salvage APR for the recurrent disease was significantly higher than that for persistent disease (p = 0.00597). For recurrent disease, OS following salvage APR was significantly higher than that following non-salvage APR (p = 0.0204); however, for persistent disease, there was no significant difference between salvage and non-salvage APR (p = 0.928). CONCLUSION: Survival outcomes following salvage APR for persistent disease were significantly worse than that for recurrent disease. Salvage APR did not improve survival outcomes for persistent disease compared to non-salvage APR. These results will elicit a review of persistent disease treatment strategies.

Comparison between preoperative chemoradiotherapy and lateral pelvic lymph node dissection in clinical T3 low rectal cancer without enlarged lateral lymph nodes.

AIM: The standard strategy for clinical T3 rectal cancer without enlarged lateral lymph nodes is preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) in Western countries and TME with bilateral lateral pelvic lymph node dissection (LPLND) in Japan. This study compared surgical, pathological and oncological results of these two strategies. METHOD: Patients who underwent preoperative CRT followed by TME in France (CRT + TME group) and those who underwent TME with LPLND in Japan (TME + LPLND group) for clinical T3 rectal adenocarcinoma without enlarged lateral lymph nodes from 2010 to 2016 were retrospectively analysed. RESULTS: In total, 439 patients were included in this study. The estimated local recurrence rate (LRR), disease-free survival and overall survival at 5 years post-surgery was 4.9%, 71% and 82% in the CRT + TME group, and 8.6%, 75% and 90% in the TME + LPLND group, respectively. Lateral LRR versus non-lateral LRR was 0.5% versus 4.2% in the CRT + TME group and 1.8% versus 6.2% in the TME + LPLND group. Obturator nerve injury and isolated pelvic abscess were shown only in the TME + LPLND group. Urinary complications were more frequent in the TME + LPLND group than in the CRT + TME group. CONCLUSION: Disease-free survival was not significantly different after TME with LPLND and after CRT followed by TME. LRR was not significantly different after both strategies; however, there was a trend for higher LRR after TME with LPLND than after CRT followed by TME. Obturator nerve injury, isolated lateral pelvic abscess and urinary complications should be noted when TME with LPLND is applied.

Two-team lateral lymph node dissection assisted by the transanal approach for locally advanced lower rectal cancer: comparison with the conventional transabdominal approach.

BACKGROUND: An optimal surgical approach to lateral lymph node dissection (LLND) remains controversial. With the recent popularity of transanal total mesorectal excision, a two-team procedure combining the transabdominal and transanal approaches was established as a novel approach to LLND. This study aimed to clarify the safety and feasibility of two-team LLND (2team-LLND) and compare its short-term outcomes with those of conventional transabdominal LLND (Conv-LLND). METHODS: Between April 2013 and March 2020, 463 patients diagnosed with primary locally advanced rectal cancer underwent a transanal total mesorectal excision; among them, 93 patients who underwent bilateral prophylactic LLND were included in this single-center, retrospective study. Among these patients, 50 and 43 patients underwent Conv-LLND (the Conv-LLND group) and 2team-LLND (the 2team-LLND group), respectively. The short-term outcomes, including the operation time, blood loss volume, number of complications, and number of harvested lymph nodes, were compared between the two groups. RESULTS: The intraoperative and postoperative complications in the 2team-LLND group were equivalent to those in the Conv-LLND group; furthermore, the incidence of postoperative urinary retention in the 2team-LLND group was acceptably low (9%). Compared with the Conv-LLND group, the 2team-LLND group had a significantly shorter operation time (P = 0.003), lower median blood loss (P = 0.02), and higher number of harvested lateral lymph nodes (P = 0.0005). CONCLUSION: The intraoperative and postoperative complications of 2team-LLND were comparable with those of Conv-LLND. Thus, 2team-LLND was safe and feasible for advanced lower rectal cancer. Moreover, it was superior to Conv-LLND in terms of the operation time, blood loss volume, and number of harvested lateral lymph nodes. Therefore, it can be a promising LLND approach.

Single-center comparative study of short-term outcomes of transanal and laparoscopic total mesorectal excisions for low and middle rectal cancers.

BACKGROUND: Transanal total mesorectal excision is a promising surgical treatment for rectal cancer. However, evidence regarding the differences in outcomes between the transanal and laparoscopic total mesorectal excisions is scarce. We compared the short-term outcomes of transanal and laparoscopic total mesorectal excisions for low and middle rectal cancers. METHODS: This retrospective study included patients who underwent low anterior or intersphincteric resection for middle (5-10 cm) or low (< 5 cm) rectal cancer at the National Cancer Center Hospital East, Japan, from May 2013 to March 2020. Primary rectal adenocarcinoma was confirmed histologically. Circumferential resection margins (CRMs) of resected specimens were measured; margins ≤ 1 mm were considered positive. The operative time, blood loss, hospitalization length, postoperative readmission rate, and short-term treatment results were compared. RESULTS: Four hundred twenty-nine patients were divided into two mesorectal excision groups: transanal (n = 295) and laparoscopic (n = 134). Operative times were significantly shorter in the transanal group than in the laparoscopic group (p < 0.001). The pathological T stage and N status were not significantly different. The transanal group had significantly lower positive CRM rates (p = 0.04), and significantly lower incidence of the Clavien-Dindo grade III (p = 0.02) and IV (p = 0.03) complications. Both groups had distal margin positivity rates of 0%. CONCLUSIONS: Compared to laparoscopic, transanal total mesorectal excision for low and middle rectal cancers has lower incident postoperative complication and CRM-positivity rates, demonstrating the safety and usefulness of local curability for middle and low rectal cancers.

Single-stapling technique versus hand-sewn anastomosis in inter-sphincteric resection with transanal total mesorectal excision (Super SST): protocol for a multicentre randomized clinical trial.

BACKGROUND: Currently, hand-sewn anastomosis is the standard procedure for inter-sphincteric resection (ISR); however, distal purse-string suturing during transanal total mesorectal excision (TaTME) has allowed a single-stapling technique (SST). Although it was originally intended for cases requiring anastomosis of 2 cm or more above the anorectal junction (ARJ), SST could be safely performed in ISR. The aim of this trial is to determine the superiority of SST over hand-sewn anastomosis in ISR with TaTME. METHODS: The Super SST trial is a multicentre randomized clinical trial comparing stapled and hand-sewn anastomoses in ISR with TaTME. The trial will recruit patients scheduled for TaTME with anastomosis below the ARJ, who will be allocated 1:1 to receive either hand-sewn or stapled anastomosis. The primary endpoint is anastomosis-related complications within 30 postoperative days. Secondary endpoints include all early and late complications, operating time, reoperation, mortality rate, length of postoperative hospital stay, readmission, incidence of anal pain and rectal mucosal prolapse, length of temporary stoma retention, the proportion of patients with a temporary stoma at 1 year after surgery, and anorectal function at 1 year after surgery. CONCLUSION: This trial will provide important clinical insights for new and promising anastomotic options for patients with very low rectal cancer. Registration number: UMIN000047818 (https://www.umin.ac.jp/ctr/index-j.htme).

Efficacy of transperineal minimally invasive surgery with laparoscopic abdominoperineal excision for lower rectal cancer.

PURPOSE: In abdominoperineal excision (APE), the advantages of the "down-to-up" approach are expected to be more obvious when performed as a two-team approach, including transperineal minimally invasive surgery (TpMIS). We investigated the efficacy of TpMIS with laparoscopic APE for lower rectal cancer. METHODS: Patients who underwent laparoscopic APE with (n = 20) or without (n = 30) TpMIS between December 2013 and April 2020 were retrospectively reviewed. Patient and tumor characteristics, intraoperative outcome, short-term outcome, and pathological findings were compared. Additional subgroup analyses were performed in technically challenging cases, including male patients, obese patients, and patients with tumors located at the anterior wall. RESULTS: There was no marked difference in the patient or tumor characteristics or short-term outcomes, including morbidity and mortality between the two groups. Pathological results were comparable, and the circumferential resection margin (CRM) positive rate was 10% in both groups. TpMIS achieved a significant reduction in operative time (p = 0.02). In a subgroup analysis, the amount of blood loss was also smaller in males (p = 0.02) and patients with a high BMI (> 25) (p = 0.005) than in others. CONCLUSION: Simultaneously performing TpMIS and laparoscopic APE is feasible owing to the favorable complication and CRM-positive rates. In terms of operative time and blood loss, TpMIS is expected to be advantageous in both easy and challenging cases.

Morphological characteristics of lateral pelvic lymph nodes in locally advanced lower rectal cancer: A retrospective study.

Aim: This study aimed to investigate the potential of the size and aspect ratio of metastatic and non-metastatic lateral pelvic lymph nodes (LPLNs) as low-risk markers for locally advanced lower rectal cancer, without treatment by neoadjuvant chemoradiation therapy or LPLN dissection. Methods: This single-center, retrospective cohort study evaluated 310 consecutive patients diagnosed with lower rectal cancer (T: T3/T4, N: any, and M: M0) who underwent curative surgery without neoadjuvant therapies between 2010 and 2018. The harvested LPLNs were categorized into groups A (metastasis-positive lymph nodes), B (metastasis-negative lymph nodes in the area bearing metastasis-positive lymph nodes), C (metastasis-negative lymph nodes in a metastasis-negative area in metastasis-positive patients), and D (lymph nodes in non-metastatic patients). The main outcome measure was the relationship among lymph node size, aspect ratio, and metastasis in the LPLNs. Results: Overall, 3962 LPLNs were harvested. The long and short axes and the aspect ratio were significantly longer and higher, respectively, in group A than in the other groups (P < .001). The aspect ratio in group B was significantly higher than that in groups C and D (P < .001). The aspect ratio in group C was significantly higher than that in group D (P < .001). Furthermore, no metastasis-positive lymph nodes had an aspect ratio of less than 0.4. Metastasis-positive LPLNs tended to be larger and rounder than their metastasis-negative counterparts. Conclusions: Metastatic LPLNs in patients with lower rectal cancer are significantly larger and have a higher aspect ratio. Lymph nodes with aspect ratios of <0.4 were metastasis negative.

Trans-anal surgery with the taTME technique for rectal gastrointestinal stromal tumors: a retrospective study.

PURPOSE: Rectal gastrointestinal stromal tumors (GISTs) surgery is often challenging owing to the anatomical constraints of the narrow pelvis and tumor hugeness. Despite the increasing number of patients undergoing trans-anal total mesorectal excision (taTME) globally, the feasibility of trans-anal surgery with the taTME technique for rectal GISTs remains unclear. We aimed to evaluate the feasibility of trans-anal surgery with the taTME technique for rectal GISTs. METHODS: Using a prospectively collected database, we retrospectively analyzed the clinical findings, surgical outcomes, pathological outcomes, urinary and anal functions, and prognoses of patients who underwent trans-anal surgery with the taTME technique for primary rectal GISTs at the National Cancer Center Hospital East from September 2014 to March 2020. RESULTS: Twenty-one patients with primary rectal GISTs were included in this study. The median distance from the anal verge to the lower edge of the tumor was 40 mm (range, 15-60 mm), and the median tumor size was 59 mm (range, 11-175 mm). Moreover, seven and 14 patients underwent one-team and two-team surgeries, respectively, with curative intent. Nineteen patients (90.5%) underwent anus-preserving surgery, and the urinary tracts were preserved in all cases. Two-team surgery showed a significantly lower blood loss volume and shorter operation time than one-team surgery (58 vs. 222 mL, P = 0.017; 184 vs 356 min, P = 0.041, respectively). The pathological negative-margin resection rate was 100%. During the follow-up period, no patient developed local GIST recurrence and one (4.8%) developed distant metastasis. CONCLUSION: Trans-anal surgery with the taTME technique is feasible for rectal GISTs, and two-team surgery may be more advantageous than one-team surgery in terms of operation time and blood loss.